Fair Value - Financial Instruments not Required to be Carried at Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Financial assets:
Investment securities held-to-maturity	$ 3,230,698	$ 3,262,509
Lease and lease commitments excluded
Financing leases	427,000	434,700
Deposit liabilities with no defined or contractual maturity	16,800,000	17,000,000
Book Value
Financial assets:
Cash and cash equivalents	1,399,035	1,170,190
Investment securities held-to-maturity	3,658,814	3,790,650
Loans	13,924,929	13,973,608
Financial liabilities:
Time deposits	3,389,505	3,298,370
Short-term borrowings	250,000	250,000
Estimated Fair Value
Financial assets:
Cash and cash equivalents	1,399,035	1,170,190
Investment securities held-to-maturity	3,230,698	3,262,509
Loans	13,454,110	13,373,785
Financial liabilities:
Time deposits	3,371,353	3,280,119
Short-term borrowings	249,772	249,312
Estimated Fair Value | Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial assets:
Cash and cash equivalents	304,624	258,057
Estimated Fair Value | Significant Other Observable Inputs (Level 2)
Financial assets:
Cash and cash equivalents	1,094,411	912,133
Investment securities held-to-maturity	3,230,698	3,262,509
Financial liabilities:
Time deposits	3,371,353	3,280,119
Short-term borrowings	249,772	249,312
Estimated Fair Value | Significant Unobservable Inputs (Level 3)
Financial assets:
Loans	$ 13,454,110	$ 13,373,785